Difference between revisions of "Lab 1 Report -- Nathan S Lachenmyer"
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==Position Calibration== | ==Position Calibration== | ||
| + | * Learned to make microfluidic devices out of double-stick tape and a slide -- this was really neat! | ||
| + | * Made two samples with 1 um microspheres | ||
| + | ** One sample with free-floating spheres (in H2O) | ||
| + | ** Another one with 'stuck' spheres in NaCl (I cheated :( ) | ||
| + | * Took a position calibration on the optical trap setup, seen below | ||
[[File:1um_cal.png]] | [[File:1um_cal.png]] | ||
calibration: 502463 Volts / m = 1.99 um / volt | calibration: 502463 Volts / m = 1.99 um / volt | ||
==Trap Stiffness Calibration== | ==Trap Stiffness Calibration== | ||
| + | * Did all three versions of the trap calibration, resulting in the following trap spring constants: | ||
{| class="wikitable" | {| class="wikitable" | ||
| Line 26: | Line 32: | ||
==Experiments== | ==Experiments== | ||
===E Coli=== | ===E Coli=== | ||
| + | * Learned to culture E Coli (sort of) | ||
| + | * Examined the various cultures to determine which ones had the fastest spinners / spinners in the appropriate direction with Steve | ||
| + | * E Coli weren't spinning very well -- swapped out the blue LED for a Red LED to determine if the wavelength made a difference | ||
| + | ** As far as we could tell, the LED color made no difference | ||
| + | ** We also couldn't figure out why the E Coli were spinning so slowly | ||
| + | * Worked with Steve to cut the flagella of E Coli by drawing them in and out of a pipette multiple times | ||
| + | ** This improved the spinning frequency of the E Coli! | ||
| + | |||
[[File:ecoli.png]] | [[File:ecoli.png]] | ||
| Line 31: | Line 45: | ||
===DNA Tethers=== | ===DNA Tethers=== | ||
| + | * Learned to make the DNA tethers | ||
| + | * Was able to trap a microsphere tethered to the slide via DNA | ||
| + | ** | ||
| + | |||
[[File:dna_raw.png]] | [[File:dna_raw.png]] | ||
| + | |||
| + | Stretchiness of the DNA: | ||
Revision as of 06:12, 12 March 2012
Contents
Calibration
All calibrations and experiments done at 20 mW.
Position Calibration
- Learned to make microfluidic devices out of double-stick tape and a slide -- this was really neat!
- Made two samples with 1 um microspheres
- One sample with free-floating spheres (in H2O)
- Another one with 'stuck' spheres in NaCl (I cheated :( )
- Took a position calibration on the optical trap setup, seen below
calibration: 502463 Volts / m = 1.99 um / volt
Trap Stiffness Calibration
- Did all three versions of the trap calibration, resulting in the following trap spring constants:
| Method | Trap Stiffness (pN / nm) |
|---|---|
| Stokes | 2.26e-5 pN/nm |
| Equipartition Theorem | 1.23e-5 pN/nm |
| PSD | *Need Bandwidth of DAQ* |
Experiments
E Coli
- Learned to culture E Coli (sort of)
- Examined the various cultures to determine which ones had the fastest spinners / spinners in the appropriate direction with Steve
- E Coli weren't spinning very well -- swapped out the blue LED for a Red LED to determine if the wavelength made a difference
- As far as we could tell, the LED color made no difference
- We also couldn't figure out why the E Coli were spinning so slowly
- Worked with Steve to cut the flagella of E Coli by drawing them in and out of a pipette multiple times
- This improved the spinning frequency of the E Coli!
The frequencies here are not properly calibrated until I get the DAQ bandwidth. There are obvious peaks at what are (now) 10, 20, and 40 Hz -- I think these are the harmonics of the e coli rotation, and once the abscissa is properly scaled will give the e coli rotation speed. There looks like there is also a peak hidden in the DC peak.
DNA Tethers
- Learned to make the DNA tethers
- Was able to trap a microsphere tethered to the slide via DNA
Stretchiness of the DNA:
